Field of the Invention
Embodiments of the present disclosure generally relate to power conversion and, more particularly, to a method and apparatus for transferring power with respect to a multi-phase AC line.
Description of the Related Art
Solar panels, or photovoltaic (PV) modules, convert energy from sunlight received into direct current (DC). The PV modules cannot store the electrical energy they produce, so the energy must either be dispersed to an energy storage system, such as a battery or pumped hydroelectricity storage, or dispersed by a load. One option to use the energy produced is to employ one or more inverters to convert the DC current into an alternating current (AC) and couple the AC current to the commercial power grid. The power produced by such a distributed generation (DG) system can then be sold to the commercial power company.
During periods of operating at low power, such as during low irradiance or when the solar irradiance on a PV module changes from no irradiance to increasing irradiance, an inverter coupled to the PV module may suffer from a lower efficiency. In order to improve the inverter efficiency during such periods, the inverter may store energy for a time period and subsequently “burst” the stored energy to the commercial power grid. When bursting power onto a multi-phase AC line, an abrupt power transfer from no power output to generating power at different levels for the various phases results in stress on components of the inverter as well as unwanted effects on the grid, such as noise, transient distortion, and flicker.
Therefore, there is a need in the art for a method and apparatus for efficiently transferring power with respect to a multi-phase line.